Drive mechanism for overhead doors



Dec. 8, 1964 J. F. M KEE ETAL DRIVE MECHANISM FOR OVERHEAD DOORS 2 Sheets-Sheet 1 14 17 Filed Sept. 28, 1961 1 V i it i E .1

Dec. 8, 1964 J. F. MOKEE ETAL DRIVE MECHANISM FOR OVERHEAD DOORS 2 Sheets-Sheet 2 Filed Sept. 28, 1961 United States Patent "ice 3,160,200 DRIVE MECHANISM FGR UVEAD DGORS John F. McKee and Reynold E. Schumacher, both of Aurora, Ill., assignors to McKee Door ompany, a corporation of lllinois Filed Sept. 28, 1961, Ser. No. 141,352 4 Claims. (Cl. 160-189) This invention relates to a drive mechanism for overhead doors of the type commonly employed in garages, service stations, industrial buildings, warehouses, and the like, and more particularly is concerned with a counterbalanced type drive mechanism having cable connection to the door and operable to pay out cable for permitting the door to lower and to take up cable for pulling the door upwardly by means of the cables.

A typical overhead door application of this type employs a counter-balance mechanism having a continuous live shaft located over the doorway and carrying cable drums anchored to the shaft and having door actuating cables leading therefrom and connected to the bottom corners of the overhead door. With larger size doors, such as are frequently used in industrial and commercial installations, it is now common practice to employ automatic motor driven operators or chain hoist drives.

Originally, the drive mechanism operated through a track mounted carriage located over the center of the door and equipped with a connection arm to the top section of the door. In this way movement of the carriage caused the connection arm to push and pull the door to closed and open positions. rangement, it sometimes occurred that the cable drums were mismatched in diameter so that one cable or the other would slack olt and jump ofr the drum or become otherwise fouled up.

It is now common to connect the drive mechanism directly to the continuous live shaft of the counter-balance mechanism and, in fact, such an arrangement is the only practical type of drive for overhead doors that'are mounted for extra clearance or high lift. In these applications, the door must first move vertically for a couple of feet before turning horizontal and a connection rod drive direct to the door is not capable of such movement.

Where a direct drive connection to the live shaft is em ployed for raising and lowering the door, it is not uncommon for one or both cables to slack otf and jump 011: the drum and become fouled so that the door can no longer be operated. To appreciate this problem, consider that the door is lying horizontally in its guideways directly above the door opening and power is applied to the live shaft at normal speed required in operating the door. The shaft winds up sooner than the door can lower of its own weight and this is the occasion where most cable fouling occurs.

Accordingly, the principal object of the present invention is to provide a slack take-up arrangement for the cable system of a power drive mechanism for overhead doors.

A more specific object of the invention is to provide a slack take-up arrangement for keeping the cables taut on the winding drums of a power driven counter-balanced continuous live-shaft type door operator.

Other objects and advantages will become apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same;

FIG. 1 is a rear elevational view of an overhead door installation embodying this invention and showing the door in closed position with parts of the arrangement being broken out to facilitate the illustration;

FIG. 2 is a fragmentary right-hand side view of a chain hoist drive for the door of FIG. 1;

Edhlflil Patented Dec. 8, 1964 FIG. 3 is an enlarged fragmentary face view of a cable tie down arrangement equipped with a slack take-up in accordance with this invention; and

FIG. 4 is a side elevational view of the tie down and slack tie up arrangement of FIG. 3.

Referring now to the drawings and particularly to FIG. 1 thereof, an articulated overhead sliding door is represented generally as 10 and comprises a plurality of horizontal sections 11 interconnected by hinges 11H. The door sections 11 are equipped with guide rollers 12 on their opposite sides that engage in side guideways 13 that lead upwardly at a slight incline and then curve to extend horizontally at a location above the door opening.

. Thus, the door 10 is mounted for upward and rearward Even with this arto pay out cable from the Winding drums 1'7.

movement from a vertical closed position across the door opening to an overhead horizontal open position.

For purposes of illustrative disclosure a counterbalanced drive mechanism designated generally as 14 is shown extending horizontally above the door opening for controlling movement of the door. The illustrated drive mechanism 14 has a continuous live shaft 15 journalled adjacent its opposite ends in suitable bearings 16 mounted to the building and equipped with cable winding drums 17 of spiral form. Each drum 17 is anchored to the shaft 15 above a side edge of the door and is fitted with a cable 18 extending down and connected to the corresponding bottom corner of the door. The illustrated live shaft 15 is comprised of shaft sections 158 arranged endto-end and rigidly interconnected by a suitable coupling 19.

Counter-balancing facilities are provided for the live shaft and in the illustrated form, each shaft section 158 is encircled along a portion of its length by a helical wire type torsion spring 20, one end of which is anchored to a wall mounted bracket 21 and the other end of which is attached to a bracket 22 mounted directly to the shaft. A chain hoist drive mechanism designated generally as 23 is shown fragmentally in FIGS. 1 and 2 as being connected directly to the live shaft.

When the door 10 is in the closed position, across the doorway, the torsion springs 20 are tightly wound and exert a torque upon the live shaft sections 153 in a direction to rotate the cable drums 17 for taking up cable and raising the door. Preferably, the torsion springs 20 substantially counter-balance the weight of the door but they are not effective to themselves raise the door.

When the door is to be raised, the drive mechanism 23 is operated to rotate the cable drums 17 in a direction to take up the cables 18, thereby pulling upwardly on the door lti'to move it to its horizontal overhead open position. During this door movement, the torsion springs 20 unwind to a predetermined minimum tension.

When the door is to be lowered from its horizontal overhead position to its vertical closed position, the drive mechanism 23 rotates the live shaft in a direction It frequently occurs that the door does not lower rapidly enough to keep the cables taut and a slack condition usually will develop during the time when the door is beginning to move downward.

In accordance with this invention, means are provided for taking up cable slack to keep the cable taut until more In the preferred embodiment illustrated herein for purposes of disclosure, the slack take-up device takes the form of a helical coil spring 27 coiled around a tie bolt 27B mounted in the opposed wings of a generally channelshaped bracket 28 that is also fixed on the lower door sec.- tion 118. The coil spring 2? has one end 27E anchored against rotation .and at its other end is provided with a generally radially extending elongated arm 27A that .terminates in a hook 27H engaging the length of cable leading from the thimble 25 up to the tie down clamp .26. The normal tautness of the cable system is sutficient for holding the arm 27A in its illustrated position adjacent the inner face of the door but the slack take-up arm 27A is swingable from this position towards an outward position to pull up a half loop of cable should slack develop during door operation.

As suggested previously, the slack take-up feature of the invention is applicable to door installations employing a motor drive in lieu of the chain hoist mechanism 23. In addition, the invention is useful Wherever the cable system is subject to slacking such as is caused by mismatched winding drums.

It should be understood that the description of the preferred form of the invention for the purpose .of complying with Section 112, Title .35, of the US. Code and that the claims should be construed as broadly as prior art will permit.

What is claimed is: K

1. A counter-balanced drive mechanism for an articulated overhead sliding door that is movable in guideways that extend upwardly alongside an opening for the door and then re,arwardly, said door having guide means carried on opposite sides of the door and engageable with said guideways for guiding movement of the door from a vertical closed position across the opening to an overhead substantially horizontal open position immediately above the .opening, said mechanism comprising means mounting a separate winding drum above and'adjacent each side of the opening to rotate about a horizontal axis, a separate cable engaged upon each drum and having a lower end connected in fixed relation to a corresponding lower side of the door, drive means connected to rotate said drums in unison either in a door opening direction or in a door lowering direction, counterbalancing means connected to said drums and acting in unison thereon to assist rotation thereof in a door opening direction and to oppose rotation thereof in a vdoor closing direction, first continuously active slack take-up means on the door adjacent one lower side thereof and connected to engage a portion of the corresponding cable adjacent but spaced from the lower end thereof to resiliently pull such cable to a taut condition, and second continuously active slack take'up means on the door adjacent the other lower side thereof and connected to engage a portion of the corresponding cable adjacent but spaced from the lower end thereof to resiliently pull such cable to a taut condition, each slack take-up means comprising a door mounted thimble having said cable portion trained reversely there- 4 zontal axis above the opening, a separate winding drum mounted on said live shaft adjacent each end thereof to rotate about said axis, a separate cable engaged upon each drum and having a lower end connected in fixed relation to a corresponding lower side of the door, drive means connected to the live shaft and selectively operable for rotating said shaft and drums in unison either in a door opening direction or in a door lowering direction, counterbalancing means connected to said live shaft and acting to assist rotation thereof in a door opening direction and acting to oppose rota-tion thereof in a door closing direction, first continuously active slack take-up means on the door adjacent one lower side thereof and connected to engage a portion of the corresponding cable adjacent but spaced from the lower end thereof to resiliently pull such cable to a taut condition, and second continuously active slack take-up means on the door adjacent the other lower side thereof and connected to engage a portion of V the corresponding cable adjacent but spaced from the lowabout for free sliding movement relative thereto, a door mounted spring mount, and an elongated coil spring located on the spring mount and having one end anchored against rotation and an opposite end providing a swingable arm terminating in a hook engaged about the cable at a point between the thimble and the lower end of the cable.

2. A counterbalanced drive mechanism for an articulated overhead sliding door that is movable in guideways that extend upwardly alongside an opening for the door and then rearwardly, said door having guide means carried on opposite sides of the door and engageable with said guideways for guiding movement of the door from a vertical closed position across the opening to an overhead substantially horizontal open position immediately above the opening, said mechanism comprising means mounting a continuous live shaft to rotate about a horior end thereof to resiliently .pull such cable to a taut condition, each slack take-up means comprising a door mounted thimble having said cable portion trained reversely thereabout for free sliding movement relative thereto, a door mounted spring mount, and an elongated coil spring located on the spring mount and having one end anchored against rotation and an opposite end providing a swingable arm terminating in a hook engaged about the cable at a point between the thim-ble and the lower end of the cable,

3. A slack take-up arrangement for a counterbalanced drive mechanism for an articulated overhead sliding door that is movable in guideways that extend upwardly alongside an opening for the door and then rearwardly, said door having guide means carried on opposite sides of the door and engageable with said guideways for guiding movement ofthe door from a vertical closed position across the opening to an overhead substantially horizon tal open position immediately above the opening, said mechanism including means mounting a continuous live shaft to rotate about a horizontal axis above the opening, a separate winding drum mounted on said live sha-ft adjacent each end thereof to rotate about said axis, a separate cable engaged upon each drum and having a lower end portion for connection to a corresponding lowor side of the door, drive means connected to the live shaft and selectively operable for rotating said shaft and drums either in a door opening direction or in a door lowering direction, and counterbalancing means connected to said live shaft and acting to assist rotation thereof in a door opening direction and acting to oppose rotation thereof in a door closing direction, said slack take-up arrangement including -a separate door mounted tie down at each lower side of the door and connected in fixed relation to the corresponding lower end portion of the cable, first continuously active slack take up means on the door adjacent one lower side thereof and connected to engage the lower end portion of the corresponding cable adjacent but spaced from the corresponding tie down to resiliently pull such cable to a taut condition, and second continuously active slack take-up means on the door adjacent the other lower side thereof and connected to engage the lower end portion of the corresponding cable adjacent but spaced from the corresponding tie down to resiliently pull such cable to a taut condition.

4. A slack take-up arrangement for a counterbalanced drive mechanism for an articulated overhead sliding door that ismovable in guideways that extend upwardly alongside an opening for the door and then rearwardly, said door having guide means carried on opposite sides of the door and engageable with said guideways for guiding movement of the door from a vertical closed position across the opening to an overhead substantially horizontal open position immediately above the opening, said mechanism including means mounting a continuous live shaft to rotate about a horizontal axis above the opening, a separate winding drum mounted on said live shaft adjacent each end thereof to rotate about said axis, a separate cable engaged upon each drum and having a lower end portion for connection to a corresponding lower side of the door, drive means connected to the live shaft and selectively operable for rotating said shaft and drums either in a door opening direction or in a door lowering direction, and counterbalancing means connected to said live shaft and acting to assist rotation thereof in a door opening direction and acting to oppose rotation thereof in a door closing direction, said slack take-up arrangement including a separate door mounted tiedown at each lower side of the door and connected in fixed relation to the corresponding lower end portion of the cable, a separate door mounted thimble beneath each tie down and having the corresponding lower end cable portion trained reversely thereabout for free sliding movement relative thereto, a door mounted spring mount on each lower side of the door, and a separate elongated coil spring 10- 6 cated on each spring mount and having one end anchored against rotation and an opposite end providing a swingable arm terminating in a hook engaged about the cable at a point between the corresponding thimble and tie down.

References Cited by the Examiner UNITED STATES PATENTS 1,916,651 7/33 Beeman et a1. 268-59 1,922,370 8/33 Johnson 20 190 1,994,142 3/35 Madsen 160-191 X 2,083,467 6/37 Morris 160 191 2,291,583 7/42 Rowe 26859 3 FOREIGN PATENTS 634,699 1/62 Canada.

HARRISON R. MOSELEY, Primary Examiner.

I. D. MEUR, CHARLES OCONNELL, Examiners. 

1. A COUNTER-BALANCED DRIVE MECHANISM FOR AN ARTICULATED OVERHEAD SLIDING DOOR THAT IS MOVABLE IN GUIDEWAYS THAT EXTEND UPWARDLY ALONGSIDE AN OPENING FOR THE DOOR AND THEN REARWARDLY, SAID DOOR HAVING GUIDE MEANS CARRIED ON OPPOSITE SIDES OF THE DOOR AND ENGAGEABLE WITH SAID GUIDEWAYS FOR GUIDING MOVEMENT OF THE DOOR FROM A VERTICAL CLOSED POSITION ACROSS THE OPENING TO AN OVERHEAD SUBSTANTIALLY HORIZONTAL OPEN POSITION IMMEDIATELY ABOVE THE OPENING, SAID MECHANISM COMPRISING MEANS MOUNTING A SEPARATE WINDING DRUM ABOVE AND ADJACENT EACH SIDE OF THE OPENING TO ROTATE ABOUT A HORIZONTAL AXIS, A SEPARATE CABLE ENGAGED UPON EACH DRUM AND HAVING A LOWER END CONNECTED IN FIXED RELATION TO A CORRESPONDING LOWER SIDE OF THE DOOR, DRIVE MEANS CONNECTED TO ROTATE SAID DRUMS IN UNISON EITHER IN A DOOR OPENING DIRECTION OR IN A DOOR LOWERING DIRECTION, COUNTERBALANCING MEANS CONNECTED TO SAID DRUMS AND ACTING IN UNISON THEREON TO ASSIST ROTATION THEREOF IN A DOOR OPENING DIRECTION AND TO OPPOSE ROTATION THEREOF IN A DOOR CLOSING DIRECTION, FIRST CONTINUOUSLY ACTIVE SLACK TAKE-UP MEANS ON THE DOOR ADJACENT ONE LOWER SIDE THEREOF AND CONNECTED TO ENGAGE A PORTION OF THE CORRESPONDING CABLE ADJACENT BUT SPACED FROM THE LOWER END THEREOF TO RESILIENTLY PULL SUCH CABLE TO A TAUT CONDITION, AND SECOND CONTINUOUSLY ACTIVE SLACK TAKE-UP MEANS ON THE DOOR ADJACENT THE OTHER LOWER SIDE THEREOF AND CONNECTED TO ENGAGE A PORTION OF THE CORRESPONDING CABLE ADJACENT BUT SPACED FROM THE LOWER END THEREOF TO RESILIENTLY PULL SUCH CABLE TO A TAUT CONDITION, EACH SLACK TAKE-UP MEANS COMPRISING A DOOR MOUNTED THIMBLE HAVING SAID CABLE PORTION TRAINED REVERSELY THEREABOUT FOR FREE SLIDING MOVEMENT RELATIVE THERETO, A DOOR MOUNTED SPRING MOUNT, AND AN ELONGATED COIL SPRING LOCATED ON THE SPRING MOUNT AND HAVING ONE END ANCHORED AGAINST ROTATION AND AN OPPOSITE END PROVIDING A SWINGABLE ARM TERMINATING IN A HOOK ENGAGED ABOUT THE CABLE AT A POINT BETWEEN THE THIMBLE AND THE LOWER END OF THE CABLE. 